PIR lights behave very strange

[cookhamjames]

Hi, brought a PIR activated wall lantern for the front door form B&Q to replace the existing non-PIR lantern. Works a treat! so brought two more to replace two non-PIR wall lanterns at the rear of my house. Wired up ok. Turn on from switch as (as stated in the leaflet) they both turn on after 5 seconds to begin their "1-2 min warm up period" after this they should both go off and only turn on during movement.

Howe ever only one goes off, the other stay on all the time. In addition the one that goes off does not come back on during any movement. The leaflet also states that if you switch the wall switch off and on within 1 second it will override the PIR and run all night. This does not work either, the one that was off stays off and the one that was on stays on! Any ideas?

 

[breezer]

check to see if they have any timers, if not you did keep the recipt didn't you?

 

[Space cat]

These things usually have some small knobs for making adjustments. The two you are most likely to find are light level and time. A third one, not always fitted, is sensitivity or range.

The light level adjustment should be set so that the light doesn't come on during daylight. Set it too low and it might not come on after dark either!

The time adjustment does what you expect. It determines how long the light stays on after it's been triggered. With bad design, it's possible that setting it too long will keep the light on permanently.

The range or sensitivity adjustment, if you have one, does exactly what it says on the tin. Set it for maximum if you want to detect movement as far away as possible. Set it lower if you're getting nuisance trips from distant objects. Set it too low and it might not detect any movement at all.

In a well designed circuit, the ranges of these adjustments would be within sensible limits, eg the sensitivity could not be reduced to zero. Unfortunately, some design engineers are incompetent while others have their hands tied by accountants demanding low production costs. To further compound the problem, the thing must work when mass produced using components that are not all identical. This is how you get dimmer switches where you can turn the knob half way round before anything changes.

 

[Steve]

The last PIR floodlight i bought from Q&B had no adjustment whatsoever.

 

[Space cat]

The last PIR floodlight i bought from Q&B had no adjustment whatsoever.

So the accountants won!

 

[cookhamjames]

Fixed it! took the light that stayed on back to B&Q, replaced it and all is well.

Moral of the story? (two really)

1. Look for the most obvious solution first

2. Don't shop at B&Q

Thanks all

 

[breezer]

you have contradicted your own item 2.

you DID buy from B & Q